FAPI-JNU is a molecule that targets fibroblast activation protein (FAP). It binds specifically to FAP, which is highly expressed in the tumor microenvironment, enabling tumor imaging and diagnosis using radionuclides [68Ga]Ga or [177Lu]Lu. The compound [177Lu]Lu−FAPI−JNU can effectively target and inhibit tumor growth in mice with tumors. FAPI-JNU holds potential for research on FAP-positive tumors, such as various solid tumors.